This invention resides in the field of catheters implantable within the human body and more particularly, relates to peritoneal catheters.
Peritoneal catheters are used in a method of treatment for kidney disease or failure known as peritoneal dialysis. The purpose of the treatment is the same as hemodialysis, that is, to remove the waste products or toxins from the blood by solute and fluid diffusion out of circulation. In hemodialysis, this is accomplished by circulating the blood outside the body through an artificial kidney in which toxins and excess fluids migrate through specific permselective membranes. In peritoneal dialysis, a solution or dialysate is introduced into the space between the abdominal wall and the thin membrane known as the peritoneum which covers the entire abdominal cavity and visceral organs. The peritoneum will act as a diffusion selective membrane for toxin removal when a proper dialysate is artificially placed in the above mentioned space. Once there, the fluid is allowed to dwell for a period of time, come to chemical equilibrium with circulating blood over several hours, and then the fluid is drained.
The cycle is repeated on a regular basis, the duration and frequency of which depends upon the patient's medical condition and the treatment regimen adopted. A catheter inserted into and extending outside the body is used for the introduction and removal of the dialysate.
A variety of peritoneal catheters exist in the prior art. Their design format is basically a flexible, straight or slightly bent tube having exit ports in the intra-abdominal portion and one or more unique design features. Such are described in Peritoneal Dialysis Bulletin, 1983 Vol. 3, No. 3, published by Peritoneal Dialysis Bulletin Inc., Toronto Western Hospital, Toronto, Ontario, Canada. These include cuffs or flanges which communicate with the walls of the body tunnel to block bacterial ingression (Tenckhoff); intra-abdominal immobilizers such as an inflatable balloon (Goldberg and Hill) or flanges (Toronto Western Hospital) to prevent catheter tip migration; and a dual columnar disc fluid distribution head positioned at the end of the intra-abdominal portion (Lifecath).
By way of background, United States Patents directed to or disclosing catheter devices include U.S. Pat. Nos. 1,626,839, Kallmeyer; 3,828,767, Spiroff; 4,173,981, Mortensen; 4,184,497, Kolff et al; 4,256,102, Monaco; 4,278,092, Borsanyi et al; 4,681,570, Dalton; and 4,687,471, Twardowski et al.
This invention disclosed herein is directed to the problem of limiting trauma to abdominal structures during dialysate introduction and to reducing the likelihood of blockage during fluid withdrawal. This may be accomplished by providing a generally flexible catheter arranged to introduce and withdraw dialysate in a smooth and uniform manner. The present invention functions to produce the above-desired result by providing in combination a catheter having a formed half helical turn arranged to be disposed within the body and a plurality of ports of decreasing size from the proximal to the distal end in the intra-abdominal portion in combination with an Ultra-low Temperature Isotropic carbon coating on the ports and the tubing.
This configuration, which consists of a structure not disclosed in the prior art known to the applicant, results in an even and wide spread distribution of fluid flow. The structure eliminates forceful streaming and catheter whip that is common in the prior art. The dialysate flowing through the bent portion of the catheter into the body undergoes a transformation from laminar flow to a spiral, rotary flow that has a radial component. Upon reaching the spatially distributed size graded ports in the intra-abdominal portion of the catheter, the fluid exits in a plurality of directions in what may be described as a gentle manner rather than with the strong directional force that will occur when either a single end port or series of in line ports are employed.
When the dialysate is removed after a dwell period, the same spacial and size graded configuration of ports results in an even, distributed withdrawal with a reduced likelihood of clogging, a problem which is of substantial concern in the use of many presently existing devices.